Substrate preparation techniques for direct investigation by TEM of single wall carbon nanotubes grown by chemical vapor deposition

Fiawoo, Mawouto; Bonnot, A.M.; Jourdain, Vincent; Michel, Thierry; Picher, Matthieu; Arenal, Raúl; Thibault-Pénisson, Jany; Loiseau, Annick

doi:10.1016/j.susc.2009.02.029

Cited by 6 publications

(2 citation statements)

References 33 publications

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“…The unusual properties of single-walled carbon nanotubes (SWCNTs) have made them the focus of many investigations aiming to correlate their exceptional mechanical and electronic behavior to their structure. − Since the discovery of SWCNTs by Iijima in 1991, researchers have been actively involved in research tending to elucidate and explore their outstanding properties that make them potentially useful for numerous technological applications. Thus, in the last years, several processes have been proposed for mass production of high quality carbon nanotubes. − However, despite their refinements − and achievements , on the selectivity toward certain diameters and chiralities, none of them has reached complete control on the resulting structure of the synthesized nanotubes. Consequently, most of the processes result in a random mixture of single-walled nanotubes with different chiralities, multiwalled nanotubes, graphite, and even amorphous carbon, which limits their technological applications since the separation methods can become difficult and expensive.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Metal−Substrate Interaction Strength on the Growth of Single-Walled Carbon Nanotubes

2011

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Single-walled carbon nanotubes are usually synthesized by catalytic growth driven by reaction of a precursor gas over metallic nanoparticles supported on a substrate. Here we use molecular dynamics simulations (MD) with the purpose of determining how the catalyst−substrate strength of adhesion influences the structure of the carbon networks synthesized on the catalyst surface. It is found that the strength of the catalyst/substrate interaction energies defines the shape of the catalyst particle. When these energies are attractive, the nanocatalyst height decreases due to enhanced wetting and in turn favors the lifting up of carbon nanotube caps during the synthesis process. In addition, the presence of an appropriate substrate may avoid catalyst poisoning. This effect may result from repulsion forces from the substrate toward catalyzed carbon atoms, which cause carbon atoms to diffuse to upper layers, thus keeping the catalyst−substrate interface exposed to continuous catalytic activity. However, too strong metal−substrate interactions may take the cluster to the limit of complete wetting, thus promoting the formation of graphene or amorphous carbon over carbon nanotube-like structures. A growth diagram is constructed in the space of metal−substrate vs metal−carbon strengths of adhesion. The growth diagram defines regions of nanotube growth and encapsulation; in the first we are able to identify also zones of higher or lower quality of the nanotubes grown. This theoretical characterization is very useful to guide a controlled synthesis.

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Section: Introductionmentioning

confidence: 99%

Effect of the Metal−Substrate Interaction Strength on the Growth of Single-Walled Carbon Nanotubes

2011

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“…Several methods for producing SWCNTs, such as laser ablation, arc discharge, , and chemical vapor deposition (CVD), have been developed in the last decades. Although these methods have achieved a high level of refinement, − they are still far from reaching complete control over important structural variables, such as nanotube length, diameter, and, especially, chirality.…”

Section: Introductionmentioning

confidence: 99%

Interplay of Catalyst Size and Metal−Carbon Interactions on the Growth of Single-Walled Carbon Nanotubes

et al. 2010

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Single-walled carbon nanotubes grow by decomposition of a carbon-containing precursor gas over metal nanocatalysts. It is known that the shape, size, and chemical nature of the catalysts play significant roles in the nucleation and growth processes. Here, we use reactive molecular dynamics simulations to analyze how the catalyst particle size and the strength of adhesion between the surface and nascent carbon structures may affect the growth process. As a result, we determine if the process leads to cap lift-off or if it causes graphitic encapsulation and, therefore, poisoning of the catalyst. In agreement with the Hafner-Smalley model, our MD simulation results illustrate that the work of adhesion must be weak enough so the curvature energy of a spherical fullerene is less favorable than that of a single-walled carbon nanotube with the same diameter, thus allowing the cap-lifting process to take place. Moreover, we propose that a simple model combining curvature energy and kinetic effects may help to identify regions of single-walled carbon nanotube growth in the phase space defined by work of adhesion, temperature, and catalyst size.

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Self-supported Pt-doped ceria nanofilms directly investigated by transmission electron microscopy

Potin

Zanfoni

Imhoff

et al. 2020

Applied Surface Science

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Substrate preparation techniques for direct investigation by TEM of single wall carbon nanotubes grown by chemical vapor deposition

Cited by 6 publications

References 33 publications

Effect of the Metal−Substrate Interaction Strength on the Growth of Single-Walled Carbon Nanotubes

Effect of the Metal−Substrate Interaction Strength on the Growth of Single-Walled Carbon Nanotubes

Interplay of Catalyst Size and Metal−Carbon Interactions on the Growth of Single-Walled Carbon Nanotubes

Self-supported Pt-doped ceria nanofilms directly investigated by transmission electron microscopy

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